β-Chitin: Molecular imaging at 0.35-nm resolution

✍ Scribed by J.-F. Revol; K. H. Gardner; H. Chanzy

• Book ID: 101718926
• Publisher: Wiley (John Wiley & Sons)
• Year: 1988
• Tongue: English
• Weight: 458 KB
• Volume: 27
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.360270213

✦ Synopsis

Organic materials are very sensitive to damage by electron beam radiation, and conventional high-resolution electron microscopy requires electron doses that destroy them. With recent developments in electron microscopes, it is now pwsible to maintain high resolution at low magnification with very weak electron exposure. This has the advantage of preserving the molecular features. On the other hand2 the images formed by the relatively small number of electrons [about 100 ynm' (1 G/A' )] are statistically poorly defined. For crystalline substrates, however, the molecular structure is periodically repeated over relatively large distances. Averaging techniques or summation procedures can thus overcome the fundamental low signal-to-noise ratio limitation,' and a clear picture of the molecules can be constructed from the fragmented information contained in each repeating unit. These techniques were first applied by Unwin